1. Field of the Invention
This invention relates to a method and apparatus for controlling a cogeneration system, particularly to a method and apparatus for controlling operation of a cogeneration system that detects exhaust gas leakage caused by blowout of an internal combustion engine.
2. Description of the Related Art
In recent years, cogeneration systems have been developed that are equipped with an internal combustion engine-driven generator for installation in an AC power supply line between a commercial power network and an electrical load for supplying power to a load in interconnection with the power network and also for supplying hot water or the like heated using exhaust heat from the engine to a thermal load. Such a cogeneration system is taught, for example, by Japanese Laid-Open Patent Application No. Hei 8-4586.
When such a cogeneration system is installed indoors, an exhaust system of the engine is connected to an exhaust duct and the exhaust gas is discharged to the exterior or outdoor therethrough, but sometimes the outlet of the exhaust duct is frozen or clogged by a bird's nest or the like. The exhaust system of the engine is also connected with a condensate water hose (tube) for discharging condensate water generated by condensation of moisture in the exhaust gas and when the exhaust duct outlet is clogged, the exhaust gas is blown out through the condensate water hose to be discharged to the exterior.
Although, in order to avoid the above disadvantageous event, an exhaust pressure switch is provided in the exhaust system to detect rise of exhaust pressure due to clogging, the exhaust pressure switch has a difficulty in detecting an abnormality of sensors and is easily affected by exhaust pulsation.